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Ecotoxicological information

Long-term toxicity to fish

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Description of key information

NOEC = 42.8 µg/L, based on analytical results; NOEC = 125 µg/L, based on nominal concentrations

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater fish:
42.8 µg/L

Additional information

The effects of the test item Isononyl benzoate to the early-life stage of fish (Zebrafish Danio rerio) were determined according to OECD guideline 210. A test was conducted under flow-through conditions with the nominal concentrations 62.5 - 125 - 250 - 500 - 1000 µg/L, corresponding to mean measured concentrations of 19.3 – 42.8 – 90.5 – 297 – 538 µg/L. The test was started by placing fertilised eggs in the test vessels and lasted 33 days (28 days post-hatch). 60 eggs of Danio reriowere exposed to the test concentrations and the control (4 replicates with 15 eggs each). Water quality parameters pH-value, oxygen concentration, temperature, hardness were determined to be within the acceptable limits. On day five 95 % of the control larvae had hatched. Therefore, study day 5 had been defined as post hatch day 0 (= PHD 0). Different toxic endpoints have been determined: egg hatch, time to hatch, fry growth (expressed as length and weight), morphological and behavioural effects, post hatch survival and fry survival. Chemical analysis (HPLC) of the test solutions was carried out in at least weekly intervals. Due to the test item properties adsorption and biodegradation were expected to occur. Therefore a flow rate equivalent to twenty test chamber volumes per 24 hours (guideline recommendation at least 5) had been set up in order to minimize absorbance and biodegradation effects. However, the mean recovery rates were in the range of 31 - 59 % of the nominal concentrations. For the lowest concentration most of the measurements were below the LOQ (0.03 mg Isononyl benzoate/L). With regard to the test item properties the analytical results were considered not to invalidate the test. All effect levels will be stated on base of both nominal and mean measured concentrations.

Findings and Observations

Based on the observation and statistical analysis of egg hatch, time to hatch, growth (expressed as weight and length), morphological and behavioural effects, post hatch survival and fry survival, the test revealed the following results:

Table1:  Hatch, Growth, Morphological Effects, Fry survival: NOEC, LOEC

Based on nominal Isononyl benzoate concentrations and mean measured concentrations in brackets, respectively.

Hatch:

Hatch on study days 3 to 5 resulted in a NOEC of ³1000 (538) µg/L and a LOEC of > 1000 (538) µg/L.

Growth1)

Length on PHD 28 resulted in a NOEC of ³ 250 (³ 90.5) µg/L and a                       LOEC of > 250 (> 90.5) µg/L1).  

Dry weight on PHD 28 resulted in a NOEC of  ³ 250 (³ 90.5) µg/L and a            LOEC of > 250 (> 90.5) µg/L.1)

Morphological and behavioural effects

Morphological and behavioural effects resulted in a                                         NOEC of³ 250(³ 90.5) µg/L and a LOEC > 250 (> 90.5) µg/L.

Post hatch survival

Post hatch survival on PHD 28 resulted in a NOEC of 250 (90.5) µg/L and a LOEC 500 (90.5) µg/L.

Overall survival

Overall survival on PHD 28 resulted in a NOEC of 125 (42.8) µg/L and a LOEC of 250 (90.5) µg/L.

Overall NOEC and LOEC

Based on the parameters hatch, growth (expressed as length and dry weight), post hatch and overall survival the overall NOEC (post hatch day 0 – 28) was 125 µg/L (42.8µg/L) and the overall LOEC was 250 µg/L (90.5 µg/L).

1) The concentrations 500 µg/L and 1000 µg/L were not considered to statistical evaluation due high mortality and reduced fish density in these replicates (number of surviving fish 80 % of the control).